THERMALING 4 BEGINNERS--Help area - Page 11 - RC Groups
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May 11, 2004, 08:44 PM
FlattyFlier's Avatar
Thanks, aeajr. I have been launching @ a 45*, but tuning it down to about 30* to get a tad better penitration in windyer conditions. I have found that it helps, and the winds helps me from stalling @ the top(like it tends to do a lot of the time for some reason)and if I get a gust at the top I can float on it for a sec and gain upto 10ft!
I will move the hook back to the rearward CG for EP(witch is about 1cm in frount of the aft glider CG and almost 2 behind the forward glider CG. I shoudl get better high, but it will not be as unstable as a "compition launch".

John, I apparently have a slightly wrong mind-set.
I usualy try to stay in my "stagnate air" for as long as I can, but as I have said before, I have had only 1 instance of true lift and a gain in altitude. But as usual, I will always try. I would do the bubble thing, but how can you see them, and if the winds are over 5mph+, they would move a tad too fast and most would pop anyway.
I looked into thermal poles and they cost too much and it wouldn't be worth it for tha amounts of time im allowed to stay out. I'd have to take them down after every setion anyway.
Would food coloring help with the visabilaty of the bubbles?
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May 11, 2004, 09:06 PM
The Airplane Gremlin
Seared Ice's Avatar
Food coloring might just make the bubbles pop easier...but you never know!
They're shiny...I think you'd see them even if they're moving at a fair clip.
Those things make tons of bubbles too...
The best thermal indicators are birds! (well...even better are other flyers...but you don't have that available)
You should read Dave Thornburg's book. I've seen the movie version of it...some great info especially about finding thermals and what the thermal indicators are.
May 11, 2004, 09:51 PM
FlattyFlier's Avatar
HE HAS A VIDEO OF THE BOOK! Great! I'll certanly look into it! Thanks.
I ALWAYS watch birds a often as I can. Even today on the ride home from school I seen a farly large(about 3m span) BOP(most likely a Hawk) circling in some lift. I watched it untill it went in for the kill.
I'll see about the bubbles, as well.
Thanks again,
May 12, 2004, 06:58 AM
Proud member of LISF and ESL
Great links Ollie.

We have viewed both of those videos during club meetings. Great info.
May 12, 2004, 07:26 AM
The Airplane Gremlin
Seared Ice's Avatar
Remember, Jake that everyone's views on how a thermal forms are different. I recommend you read as many of these views as you can, then go by whichever one you feel happens in real life in your area. I think the difference between all these views is simply the area that people live. Here, as long as the sun's out, we get distinct cylindrical haze, its big mushy clouds there are weak, but distinct thermals...later in the day there are almost no thermals.

A great example of how thermalling views differ is that the second video of those two says that in sink, the plane will point down and in lift it will point up. In Dave Thornburg's movie, he says that in lift the plane will point down and in sink it will point up! I havn't been in strong enough lift or sink to know yet how my plane and thermals interact.

When you're flying, make sure to always keep your eyes on those birds. Just having your plane in the air will usually attract big birds (they think you might be one of their friends...or enemies!) and then once they figure out that you're just a big floating peice of wood and not something to make friends with or eat, they will begin their regular thermalling and looking for rabits to eat. Now you've got yourself 4 or 5 perfect thermal indicators all over the sky!

May 12, 2004, 07:46 AM
Registered User
Dr. Drela says that pitch changes when flying through vertical shear. Nose goes up entering a thermal and down exiting lift. I agree.

I also say low altitude thermals (plumes) aren't all smooth and there can be variations in shear within the generally rising air mass that can change pitch either way while the plane is rising at various rates in lift. While many people rely on pitch change to identify lift, I say it is not so much a guarantee of lift as it is a guarantee of vertical shear that is hard to reliably correlate with lift.
May 12, 2004, 07:50 AM
FlattyFlier's Avatar
Ive flown with birds several times and they usualy don't stick around long, but they have found slope lift for me, but it wasn't within my glideing range to get out to it
YOur discription of thermals is about what happoneds here. But we do get boomers(big ones!) But they are usualy too high for my lil' 2m to get to. My plane does go into a tail high attitude in lift and just levels out and sinks when in sink. But the wings dipping are better indicators than pitch.
May 12, 2004, 05:56 PM
FlattyFlier's Avatar
HEY!! What about a smoke machine? They can make pritty dinse smoke if needed and won't pop!
(Got the idea from the Secrets of Thermals.wmv trailer vid from: that showed a plume of dust being sucked into a thermal after being stured up by a passing trackor.
That is truely the neatest thing ive ever seen. That alone is enough to get me to buy the vid just to see that again!
May 12, 2004, 07:13 PM
Registered User
tsunami's Avatar
that sounds like itll work great now were to get a smoker
May 12, 2004, 07:49 PM
FlattyFlier's Avatar
May 15, 2004, 09:47 PM
FlattyFlier's Avatar
Bad new again, ya'll.
My Aspire has been crashed again.
The up-start line just wouldnt come off and the shoot gto all wraped aroud the wing from the slack in the line and the wind and when I tryed to bring her in for an E-landing and a gusts of wind pushed her just far enough to put enough tention on the line to pull her strait in and it broke all the newly rebuilt part off.
This re-build will be faster, but harder becasue the canopy mount is broke/gone and acouple other things that were not hurt the last time.
Oh, well.
I'll be gettin gto it sometime...
But I did see a VERY nice and somewhat large Thermal(see as in about 10 BOP circleing in ti abot 200-300ft up.
It only lasted about 1 min. but that was enough for me to check it out and try to thermal my P-51(GWS) in it, but I wasnt able to climb fast enough.
May 15, 2004, 10:59 PM
Proud member of LISF and ESL
Are you hi-starting the plane with the motor in it?????

May 16, 2004, 10:46 AM
FlattyFlier's Avatar
No, the motor was not on it.
May 29, 2004, 09:55 AM
FlattyFlier's Avatar
It has been too windy to fly this past week, so I did some work on the Aspire, but shes not fixed/done yet.
But I also built a GWS Slwo STick and J3-F witch are both "big" and light! Great for thermaling.
It has also been cool @ night but then gets humid and hot about 12:00, is this good thermal weather? I want to practice thermaling with my SS and J3 while the Aspire is out of commition.